Sub-sea chemical injection metering valve

ABSTRACT

An apparatus that includes a chemical injection management system. The chemical injection management system may include an interface configured to couple the chemical injection management system to a mineral extraction system. In addition, the chemical injection management system may include an ultrasonic flow meter.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and benefit of U.S. Non-Provisionalpatent application Ser. No. 13/063,924, entitled “Sub-Sea ChemicalInjection Metering Valve,” filed Mar. 14, 2011, which is hereinincorporated by reference in its entirety, which claims priority to andbenefit of PCT Patent Application No. PCT/US2009/061732, entitled“Sub-Sea Chemical Injection Metering Valve,” filed Oct. 22, 2009, whichis herein incorporated by reference in its entirety, and which claimspriority to and benefit of U.S. Provisional Patent Application No.61/120,227, entitled “Sub-Sea Chemical Injection Metering Valve”, filedon Dec. 5, 2008, which is herein incorporated by reference in itsentirety.

BACKGROUND

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the present invention,which are described and/or claimed below. This discussion is believed tobe helpful in providing the reader with background information tofacilitate a better understanding of the various aspects of the presentinvention. Accordingly, it should be understood that these statementsare to be read in this light, and not as admissions of prior art.

Wells are often used to access resources below the surface of the earth.For instance, oil, natural gas, and water are often extracted via awell. Some wells are used to inject materials below the surface of theearth, e.g., to sequester carbon dioxide, to store natural gas for lateruse, or to inject steam or other substances near an oil well to enhancerecovery. Due to the value of these subsurface resources, wells areoften drilled at great expense, and great care is typically taken toextend their useful life.

Chemical injection management systems are often used to maintain a welland/or enhance throughput of a well. For example, chemical injectionmanagement systems are used to inject corrosion-inhibiting materials,foam-inhibiting materials, wax-inhibiting materials, and/or antifreezeto extend the life of a well or increase the rate at which resources areextracted from a well. Typically, these materials are injected into thewell in a controlled manner over a period of time by the chemicalinjection management system.

The life of a chemical injection management system may be limited by itsmechanical components, such as gearboxes, motors, and valves that canwear out. Further, sensors and actuators used to control flow rate candrift over time, and, as a result, the accuracy of the chemicalinjection management system can decline. These problems may beparticularly acute in sub-sea applications, where the chemical injectionmanagement system may be difficult and/or expensive to access. Replacinga worn out or inaccurate chemical injection management system cansignificantly add to the cost of operating a well, for instance.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentinvention will become better understood when the following detaileddescription of certain exemplary embodiments is read with reference tothe accompanying drawings in which like characters represent like partsthroughout the drawings, wherein:

FIG. 1 is a perspective view of an exemplary resource extraction systemin accordance with an embodiment of the present technique;

FIG. 2 is a partial perspective view of the resource extraction systemof FIG. 1 that depicts an exemplary chemical injection management systemand a valve receptacle in accordance with an embodiment of the presenttechnique;

FIG. 3 is a rear-perspective view of the chemical injection managementsystem of FIG. 2;

FIG. 4 is a perspective view of the valve receptacle of FIG. 2;

FIG. 5 is a cutaway view of the chemical injection management system ofFIG. 2;

FIG. 6 is a side-view of an exemplary flow regulator in accordance withan embodiment of the present technique;

FIG. 7 is a cross-sectional view of an exemplary valve in accordancewith an embodiment of the present technique;

FIG. 8 is a diagrammatic view of the flow regulator of FIG. 6;

FIG. 9 is a cross-sectional view of an exemplary pressure equalizer inaccordance with an embodiment of the present technique;

FIG. 10 is a flowchart depicting an exemplary pressure equalizationprocess in accordance with an embodiment of the present technique;

FIG. 11 is a cross-sectional diagrammatic representation of an exemplaryultrasonic flow meter used with the flow regulator in accordance with anembodiment of the present technique;

FIG. 12 is a graph depicting needle position versus flow coefficient forthe valve of FIG. 7;

FIG. 13 is a flowchart depicting an exemplary valve-adjustment procedurein accordance with an embodiment of the present technique;

FIG. 14 is a cross-sectional view of another exemplary ultrasonic flowmeter used with the flow regulator in accordance with an embodiment ofthe present technique;

FIG. 15 is a cross-sectional view of an exemplary chemical injectionmanagement system insert configured to lock into place within analternative chemical injection management system receptacle, illustratedin FIG. 16;

FIG. 16 is a cross-sectional view of an exemplary alternative chemicalinjection management system receptacle within which the chemicalinjection management system insert of FIG. 15 may lock into place;

FIG. 17 is a cross-sectional view of the chemical injection managementsystem insert of FIG. 15 locked into place within the chemical injectionmanagement system receptacle of FIG. 16;

FIG. 18 is a perspective view of the chemical injection managementsystem insert of FIG. 15 locked into place within the chemical injectionmanagement system receptacle of FIG. 16; and

FIG. 19 is a cross-sectional view of an exemplary chemical injectionmanagement system insert containing multiple chemical injectionmanagement systems.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

One or more specific embodiments of the present invention will bedescribed below. These described embodiments are only exemplary of thepresent invention. Additionally, in an effort to provide a concisedescription of these exemplary embodiments, all features of an actualimplementation may not be described in the specification. It should beappreciated that in the development of any such actual implementation,as in any engineering or design project, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which may vary from one implementation toanother. Moreover, it should be appreciated that such a developmenteffort might be complex and time consuming, but would nevertheless be aroutine undertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure.

When introducing elements of various embodiments of the presentinvention, the articles “a,” “an,” “the,” and “said” are intended tomean that there are one or more of the elements. The terms “comprising,”“including,” and “having” are intended to be inclusive and mean thatthere may be additional elements other than the listed elements.Moreover, the use of “top,” “bottom,” “above,” “below,” and variationsof these terms is made for convenience, but does not require anyparticular orientation of the components.

Certain exemplary embodiments of the present invention include achemical injection management system that addresses one or more of theabove-mentioned inadequacies of conventional chemical injectionmanagement systems. Some embodiments may include a flow regulator thatincludes one or more non-invasive flow meters, such as ultrasonic flowmeters. The use of non-invasive flow meters in the chemical injectionmanagement system may minimize the need for frequent tuning and/orreplacement of the flow meters. In particular, since non-invasive flowmeters may generally include fewer moving mechanical parts, the extentof mechanical wear over time may be minimized. As such, the non-invasiveflow meters may experience longer life cycles and may maintainmeasurement accuracy longer than other types of flow meters.

In some embodiments, the flow regulator may also be configured toexercise direct, feed-forward control of a valve, without using a nestedvalve-positioning feedback control loop. As explained below, flowregulators exercising feed-forward control of the valve may remainaccurate over longer periods of time than systems exercising feedbackcontrol, which relies on system constants that may not be appropriatewhen valve components have worn or other conditions have changed.

Additionally, or alternatively, some embodiments may immerse componentsof the chemical injection management system in a protective fluid, suchas oil, to reduce wear on moving components and potentially extend theiruseful life. To this end, some embodiments may have a sealed housing tocontain the protective fluid and a pressure equalizer to reducehydrostatic loads in sub-sea applications, as explained below. Prior toaddressing these features in detail, aspects of a system that may employsuch a chemical injection management system are discussed.

FIG. 1 depicts an exemplary resource extraction system 10 that mayinclude a well 12, what is colloquially referred to as a “christmastree” 14 (hereinafter, a “tree”), a chemical injection management system16, and a valve receptacle 18. The illustrated resource extractionsystem 10 can be configured to extract hydrocarbons (e.g., oil and/ornatural gas). In some embodiments, the resource extraction system 10 maybe land-based or disposed a sub-sea, and/or configured to extract orinject other substances, such as those discussed above.

When assembled, the tree 14 may couple to the well 12 and include avariety of valves, fittings, and controls for operating the well 12. Thechemical injection management system 16 may be coupled to the tree 14 bythe valve receptacle 18. The tree 14 may place the chemical injectionmanagement system (C.I.M.S.) 16 in fluid communication with the well 12.As explained below, the chemical injection management system 16 may beconfigured to regulate the flow of a chemical through the tree 14 andinto the well 12.

FIG. 2 is a perspective view of the chemical injection management system16 mated with the valve receptacle 18. As illustrated, the chemicalinjection management system 16 may include a flow regulator 20, apressure equalizer 22, a housing 24, a tree interface 26, and an ROV(remotely operated vehicle) interface 28. As described in reference toFIGS. 5-8, the flow regulator 20 may include components that reduce thelikelihood of the flow regulator 20 losing accuracy over time.Furthermore, the pressure equalizer 22 may facilitate the inclusion of aprotective fluid, which is believed to extend the life of movingcomponents within the housing 24. Prior to addressing these features indetail, other components of the chemical injection management system 16are discussed.

With reference to FIGS. 2 and 3, the housing 24 may include an outer-endplate 46, a side wall 48, a handle 50, an inner-end plate 52, and atree-interface shield 54. The side wall 48 and end plates 46 and 52 maybe made from a generally rigid, corrosion-resistant material and maygenerally define a right cylindrical volume with a circular base. Thetree-interface shield 54 may extend from the side wall 48 beyond theinner-end plate 52. The handle 50 may be affixed (for example, welded)to the side wall 48 and may have a U-shape. Some embodiments may includeadditional handles 50.

As illustrated by FIG. 3, the tree interface 26 may include a key 56,guide pins 58 and 60, a latch 62, an electrical connector 64, afluid-inlet connector 66, and a fluid-outlet connector 68. In thepresent embodiment, with the exception of the key 56, the components ofthe tree interface 26 may be generally disposed within thetree-interface shield 54. These components may be configured toelectrically, fluidly, and/or mechanically couple the chemical injectionmanagement system 16 to the tree 14 via complementary components on thevalve receptacle 18, as explained below after discussing the ROVinterface 28.

The ROV interface 28 will now be described with reference to FIGS. 2 and5. The illustrated ROV interface 28 may include apertures 70, a flaredgrip 72, slots 74 and 76, and a torque-tool interface 78. In someembodiments, the ROV interface 28 may be an API 17D class 4 ROVinterface. The ROV interface 28 may be attached to the outer-end plate46. The torque-tool interface 78, which may be configured to couple to atorque tool on an ROV, may be disposed within the flared grip 72 andgenerally symmetrically between the slots 74 and 76.

As illustrated by FIG. 5, the torque-tool interface 78 may be coupled toan internal drive mechanism that includes a driveshaft 80, a threadedcoupling 82, and a cam 84 that is linked to the latch 62. The operationof these components will be described after discussing features of thevalve receptacle 18.

FIGS. 2 and 4 illustrate the exemplary valve receptacle 18. Startingwith the features depicted by FIG. 2, the valve receptacle 18 mayinclude a fluid inlet 86, a fluid outlet 88, an electrical connection90, a mounting flange 92, a keyway 94, support flanges 96, an outerflange 98, a valve aperture 100, a valve tray 102, and tray supports104. The fluid inlet 86 may be a fluid conduit, tube, or pipe that is influid communication with a fluid source, such as a supply of a liquid tobe injected, and the fluid outlet 88 may be a fluid conduit, tube, orpipe that is in fluid communication with the well 12. The electricalconnection 90 may couple to a power source, a user input device, adisplay, and/or a system controller. The mounting flange 92 may beconfigured to couple the valve receptacle 18 to the tree 14. The keyway94 and the valve tray 102 may be configured to at least roughly alignthe chemical injection management system 16 to the valve receptacle 18during installation of the chemical injection management system 16.Specifically, the valve support tray 102 may be configured to supportthe chemical injection management system 16 as it slides into the valveaperture 100, and the key 56 may be configured to slide into the keyway94 to rotationally position the chemical injection management system 16.

Turning to the features illustrated by FIG. 4, the valve receptacle 18may include a slot 106, lead-in chamfers 108 and 110, chamferedapertures 112 and 114, a complementary electrical connector 116, acomplementary fluid-inlet connector 118, and a complementaryfluid-outlet connector 120. In the present embodiment, these componentsmay be disposed within the valve aperture 100. The lead-in chamfers 108and 110 and the slot 106 may be configured to align and receive thelatch 62 from the chemical injection management system 16, and thechamfered apertures 112 and 114 may be configured to receive the guidepins 58 and 60, respectively. Additionally, the complementaryfluid-inlet connector 118 may be configured to fluidly couple the fluidinlet 86 to the fluid-inlet connector 66, and the complementaryfluid-outlet connector 120 may be configured to fluidly couple the fluidoutlet 88 to the fluid-outlet connector 68. The complementary electricalconnector 116 may be configured to electrically couple the electricalconnector 64 on the chemical injection management system 16 to theelectrical connection 90.

During installation, the chemical injection management system 16 may besecured to an ROV above or near the surface of the ocean, e.g., on asupport structure or vessel. The ROV may then submerge and convey thechemical injection management system 16 to the tree 14 and place it onthe valve tray 102. The ROV may rotate the chemical injection managementsystem 16 to align the key 56 with the keyway 94. The ROV may then drivethe chemical injection management system 16 forward into the valveaperture 100, as indicated by arrow 121 in FIG. 2. As the chemicalinjection management system 16 moves forward, the guide pins 58 and 60may mate or cooperate with the chamfered apertures 112 and 114 tofurther refine the alignment of the chemical injection management system16. With further forward movement, the latch 62 may be inserted throughthe slot 106 with the aid of the lead in chamfers 108 and 110.

To form the electrical and fluid connections, a torque tool on the ROVmay then rotate the torque-tool interface 78, which may rotate thedriveshaft 80 within the cam 84. The cam 84 may transmit approximatelythe first 90° of rotation of the driveshaft 80 into rotation of thelatch 62, thereby positioning the latch 62 out of alignment with theslot 106 and generally preventing the latch 62 from being pulled backthrough the slot 106. After 90° of rotation, the cam 84 may generallycease transmitting rotation of the driveshaft 80, and the threadedcoupling 82 may convert rotation of this driveshaft 80 into a lineartranslation or pulling of the latch 62 back towards the housing 24.However, because the latch 62 is out of alignment with the slot 106, itmay be generally prevented from moving backwards by the valve receptacle18. As the latch 62 is pulled backwards, the chemical injectionmanagement system 16 may gradually translate forward, and the electricaland fluid connections may be formed. Finally, the ROV may disengage fromthe chemical injection management system 16 and return to the surface.

Features of the flow regulator 20 will now be described with referenceto FIGS. 5-8. FIG. 5 illustrates the flow regulator 20 within a cutawayportion of the housing 24, and a FIG. 6 illustrates the flow regulator20 in isolation. FIG. 7 is a cross-sectional view of a valve that may beemployed in the flow regulator 20, and FIG. 8 is a diagrammaticrepresentation of the flow regulator 20.

Turning to FIG. 6, flow regulator 20 may include fluid conduits 122,124, and 126, a valve 128, a valve drive 130, a flow meter 132, and acontroller 134. As explained below, the flow regulator 20 may beconfigured to regulate or control a flow parameter, such as a volumetricflow rate, a mass flow rate, a volume, and/or a mass of fluid flowinginto the well 12.

Features of the exemplary valve 128 are depicted in the cross-sectionalview of FIG. 7. The valve 128 may include a body 136, a threaded inlet138, a needle seat 140, a needle 142 seals 144, 146, and 148, and anoutlet manifold 150. The illustrated needle seat 140 may includeapertures 152 and a narrowed fluid path 154. The needle 142 may beconfigured to linearly translate through the body 136, as indicated byarrow 156, and may include a tapered tip 158 disposed generally withinthe needle seat 140.

In operation, a fluid may flow in through the threaded inlet 138, passthrough the needle seat 140, and flow out of the valve 128 throughconduit 124, which may be coupled to be outlet manifold 150. The needle142 may be moved as indicated by arrow 156 to control the flow ratethrough the valve 128. As the needle 142 is withdrawn or moved upwards,a gap between the tapered tip 158 and the narrowed fluid path 154 of theneedle seat 140 may expand, and the flow rate may increase. Conversely,as the needle 142 is driven into the body 136 or moved downwards, thegap between the tapered tip 158 and the narrowed fluid path 154 maydecrease, and the flow rate through the valve 128 may decrease. That is,the flow rate through the valve 128 may generally correspond with theposition of the needle 142. The valve 128 may have a turndown ratiogreater than or equal to 100:1, and some embodiments may include two ormore valves 128 that are each sized for different flow rates.

Returning to FIG. 6, the illustrated valve drive 130 may include a motor160, a gearbox 162, and a control signal path 164. The motor 160 mayhave a direct-current (DC) motor, for instance, a 24 volt DC electricmotor with. In certain embodiments, the gearbox 162 includes a highpower ratio planetary gearbox with a gear ratio in excess of 600:1. Insome embodiments, these components 160 and 162 may be immersed in anoil-filled environment, as explained below. Advantageously, such anenvironment may tend to reduce wear on these components 160 and 162.

The flow meter 132 may include a fluid inlet 166, a fluid outlet 168,and a measurement signal path 170. In some embodiments, the flow meter132 may be an ultrasonic flow meter, as described in greater detailbelow with respect to FIGS. 11 and 14. That is, the flow meter 132 maybe configured to measure a flow rate or amount of fluid by transmittingacoustic energy along one or more paths through which the fluid flows.The flow meter 132 may be generally free of bearings and othermechanical components and generally chemically resistant. Additionally,in some embodiments, the flow meter 132 may be rated for pressuresgreater than the 5 kilopounds per square inch (ksi), 10 ksi, 15 ksi, or20 ksi.

The controller 134 may include a processor 172 and memory 174. Thecontroller 134 may be configured to determine a volumetric flow rate, amass flow rate, a volume, or a mass based on a signal from the flowmeter 132. The controller 134 may also be configured to regulate orcontrol one or more of these parameters based on the signal from theflow meter 132 by signaling the motor 160 to adjust the position of theneedle 142. To this end, the controller 134 may include software and/orcircuitry configured to execute a control routine, such as aproportional-integral-differential (PID) control routine. In someembodiments, the control routine and/or data based on the signal fromthe flow meter 132 may be stored in memory 174 or anothercomputer-readable medium.

FIG. 8 is a diagrammatic representation of the flow regulator 20.Starting with the connections configured to convey fluids, thefluid-inlet connector 66 may be fluidly coupled to the threaded inlet138 of the valve 128 by fluid conduit 122. The fluid outlet manifold 150of the valve 128 may be fluidly coupled to the fluid inlet 166 of theflow meter 132 by the fluid conduit 124. Additionally, the fluid outlet168 of the flow meter 132 may be fluidly coupled to the fluid-outletconnector 68 by fluid conduit 126. Turning to the connections configuredto convey information, data, and/or control signals, the controller 134may be communicatively coupled to the flow meter 132 by measurementsignal path 170 and to the valve drive 130 by control signal path 164.Additionally, the controller 134 may be communicatively coupled to theelectrical connector 64 for communication with other components of theresource extraction system 10 and for a source of power. The needle 142mechanically links the valve drive 130 and the valve 128.

In operation, the controller 134 may exercise feedback control overfluid flow through the flow regulator 20. The controller 134 maytransmit a control signal to the valve drive 130. The content of thecontrol signal may be determined by, or based on, a comparison between aflow parameter (e.g., a volumetric flow rate, a mass flow rate, avolume, or a mass) measured by the flow meter 132 and a desired value ofthe flow parameter. For instance, if the controller 134 determines thatthe flow rate through the flow regulator 20 is less than a desired flowrate, the controller 134 may signal the valve drive 130 to withdraw theneedle 142 some distance. In response, the motor 160 may drive thegearbox 162, and the gearbox 162 may convert rotational movement fromthe motor 160 into linear translation of the needle 142. As a result, insome embodiments, the flow rate through the valve 128 may increase asthe gap between the tapered tip 158 of the needle 142 and the narrowedfluid path 154 of the needle seat 140 increases. Alternatively, if thecontroller 134 determines that the flow rate (or other flow parameter)through the flow regulator 20 is greater than a desired flow rate (orother flow parameter), the controller 134 may signal the valve drive 130to drive the needle 142 some distance into the valve 128, therebypotentially decreasing the flow rate. In other words, the controller 134may signal the valve drive 130 to move the needle 142 some distancebased on a flow parameter sensed by the flow meter 132.

To control the flow parameter, the controller 134 may exercise feedbackand/or feed-forward control of the valve drive 130. For instance, insome embodiments, the controller 134 may receive a drive feedback signal175 that is indicative of, or correlates with, the position of theneedle 142. Using the drive feedback signal 175, the controller 134 mayexercise feedback control over the position of the needle 142. That is,the controller 134 may send a control signal 164 that is determined, atleast in part, by a comparison between the drive feedback signal 175 anda desired needle position. The desired needle position may be determinedby a table, equation, and/or relationship stored in memory 174 thatcorrelates needle position with flow rate through the valve 128.Embodiments employing feedback control over both the position of theneedle 142 and the flow parameter may be characterized as having anested control loop, e.g., a feedback control loop directed towardcontrolling the needle position nested within a feedback control loopdirected towards controlling the flow parameter.

Some embodiments may not include a nested control loop or may employ anested control loop in a more limited fashion. For instance, in someembodiments, the controller 134 may not receive the drive feedbacksignal 175 or may partially or entirely disregard the drive feedbacksignal 175. In certain embodiments, the controller 134 may exercisefeed-forward control over the position of the needle 142. That is, thecontroller 134 may transmit control signal 164 to the valve drive 130based on a difference between a desired flow parameter value and ameasured flow parameter value, regardless of a current position of theneedle 142. In other words, some embodiments may not rely on a storedcorrelation between needle position and flow rate through the valve 128.For instance, in operation, the controller 134 may determine that thecurrent volumetric flow rate through the flow regulator 20 is less thanthe desired volumetric flow rate and, in response, signal the valvedrive 130 to shift the position of the needle 142 some distance. In someembodiments, the controller 134 may determine this distance withoutregard to the current position of the needle 142.

Advantageously, embodiments without a nested control loop may controlflow parameters more accurately over a longer period of time and under awider variety of circumstances than conventional systems. Because someembodiments do not rely on a correlation between the position of theneedle 142 and a flow rate through the valve 128, they may be morerobust in the face of changing conditions. For example, the tapered tip158 of the needle 142 or the narrowed fluid path 154 of the needle seat140 may wear and change the relationship between the position of theneedle 142 and the flow rate through the valve 128. Such a change couldintroduce error when exercising feedback control of the position of theneedle 142. In some circumstances, this error could decrease theresponsiveness, stability, or accuracy of the flow regulator 20. Incontrast, embodiments without a nested control loop for controlling theposition of the needle 142 may be affected less by these sources oferror.

Other features of the chemical injection management system 16 may tendto extend its useful life. For example, returning to FIG. 5, an interior181 of the housing 24 may be partially or substantially entirely filledwith a protective fluid 182, such as oil. In some embodiments, theprotective fluid 182 may be hydraulic gear oil. Advantageously, theprotective fluid 182 may lubricate and/or tend to reduce wear oncomponents inside the housing 24, such as the driveshaft 80, the cam 84,the threaded coupling 82, and/or the valve drive 130. To maintainseparation of seawater and the protective fluid 182, the housing 24 maybe substantially watertight. In some sub-sea applications, a differencein pressure between the protective fluid 182 and surrounding seawatermay exert a hydrostatic load on the housing 24. To reduce this load, thechemical injection management system 16 may include a pressure equalizer22.

Features of the exemplary pressure equalizer 22 will now be describedwith reference to FIGS. 2, 5, 9, and 10. As illustrated by FIGS. 2 and5, the pressure of equalizer 22 may include one or more bladders 184 andfittings 186. The pressure equalizer 22 may extend inward into thehousing 24 from the outer-end plate 46. Some embodiments may include 1,2, 3, 4, 5, or more bladders.

FIG. 9 illustrates a cross-sectional view of the exemplary pressureequalizer 22. The bladder 184 may be made of a resilient and/orwatertight material, such as rubber, neoprene, vinyl, or silicone. Thebladder 184 may have a generally cylindrical shape and couple to thefitting 186 at one end.

The illustrated fitting 186 may include a water inlet 188, sealingmembers 190 and 192, and an O-ring seat 194. The water inlet 188 mayextend through the fitting 186 and provide a fluid passage into thebladder 184. The sealing member 190 may seal the bladder 184 to thefitting 186. The sealing member 192 and O-ring seat 194 may cooperatewith an aperture in the outer-end plate 46 to secure the fitting 186 tothe outer-end plate 46 and form a generally watertight seal with theouter-end plate 46. In some embodiments, the fitting 186 may includethreads that cooperate with complementary threads on the outer-end plate46 and/or a threaded nut disposed outside of the outer-end plate 46.

In operation, the pressure equalizer 22 may tend to reduce a differencein pressure between the protective fluid 182 and surrounding waterpressure. The forces from surrounding water pressure on the bladder 184are depicted by arrows 196 in FIG. 9, and the forces from the pressureof the protective fluid 182 are illustrated by arrows 198. If the waterpressure 196 is greater than the pressure of the protective fluid 198,the bladder 184 may expand and/or apply a force to the protective fluid182 and increase the pressure 198 of the protective fluid 182, therebypotentially reducing the pressure differential. In some embodiments, theprotective fluid 182 may be substantially incompressible and the bladder184 may primarily transmit a force rather than expand to equalizepressure.

Some embodiments may include other types of pressure equalizers 22, suchas a piston disposed within a cylinder that is in fluid communicationwith the protective fluid 182 and surrounding seawater on respectiveopposite sides of the piston. In another example, the pressure equalizer22 may include a resilient or less rigid portion of the housing 24 thatis configured to transmit a force to the protective fluid 182.

FIG. 10 illustrates an exemplary pressure equalization process 200. Theprocess 200 may include receiving a force arising from water pressure,as indicated by block 202, and/or reducing a pressure differentialbetween the water pressure and the pressure of a protective fluid bytransmitting the force to the protective fluid, as indicated by block204. Reducing the pressure differential may include substantiallyeliminating the pressure differential or substantially reducing themagnitude of the pressure differential. In some land-based applications,the process 200 may include receiving a force arising from air pressureand transmitting the force to the protective fluid.

As described above, the flow meter 132 of the flow regulator may be anultrasonic flow meter. In general, ultrasonic flow meters measure thetransit time of ultrasonic energy pulses traveling with or against theflow of a fluid being measured. More specifically, ultrasonic flowmeters generally include at least one pair of transducers on oppositesides of a measurement pipe through which the fluid flows. For instance,FIG. 11 is a cross-sectional diagrammatic representation of an exemplaryultrasonic flow meter 132 used with the flow regulator 20. Asillustrated, a first transducer 206 and a second transducer 208 arelocated on opposite sides of a measurement pipe 210. In particular, thefirst transducer 206 and the second transducer 208 may form an acousticpath 212 across the fluid flow path 214. As illustrated, the acousticpath 212 may, for example, form a diagonal line across a longitudinalaxis 216 of the measurement pipe 210. More specifically, the acousticpath 212 may form an angle of θ between the acoustic path 212 and a lineperpendicular to the longitudinal axis 216.

The ultrasonic flow meter 132 of FIG. 11 may transmit acoustic energyalong the acoustic path 212 (i.e., from the first transducer 206 to thesecond transducer 208) through the measurement pipe 210 within which thefluid flows. More specifically, the first transducer 206 may be excitedby a burst of electrical energy. This may cause a pulse of acousticenergy into the adjacent medium. In certain embodiments, the ultrasonicpulse may consist of several cycles having a frequency in the range of0.05 to 3 megahertz (mHz). The transducers 206, 208 are generallydesigned to be directional. In other words, a significant portion of theacoustic energy will travel along the acoustic path 212 from the firsttransducer 206 to the second transducer 208. The elapsed time from thetime of transmission from the first transducer 206 to the time ofdetection by the second transducer 208 may be measured.

Conversely, the second transducer 208 may also be excited by a burst ofelectrical energy. This may cause another pulse of acoustic energy intothe adjacent medium. Again, a significant portion of the acoustic energywill travel along the acoustic path 212 from the second transducer 208to the first transducer 206. The elapsed time from the time oftransmission from the second transducer 208 to the time of detection bythe first transducer 206 may also be measured. Each energy pulsetraverses at least substantially or exactly the same acoustic path 212.Therefore, the difference in the transit times, as well as theparticular geometries of the measurement pipe 210 (e.g., the innerdiameter (ID)) and the acoustic path 212 (e.g., the angle θ), may beused to calculate fluid velocity and volumetric flow rate of the fluid.

In addition, although illustrated in FIG. 11 as utilizing an acousticpath 212 with an angle θ of approximately 45 degrees, the angle θ of theacoustic path 212 may vary depending on specific parameters of theultrasonic flow meter 132 (e.g., operating conditions, spaceconstraints, and so forth). For instance, the angle θ may be 0 degrees(i.e., perpendicular to the longitudinal axis 216), 15 degrees, 30degrees, 45 degrees, and so forth. Indeed, as explained in furtherdetail below with respect to FIG. 14, the angle θ may be as great as 90degrees, such as when the transducers 206, 208 are placed at oppositeends of the fluid flow path 214. In addition, in certain embodiments, aplurality of paired transducers 206, 208 may be used at varying anglesθ, such that multiple sets of measurement data may be collected by theultrasonic flow meter 132. Also, in certain embodiments, a plurality ofpaired transducers 206, 208 may be located radially around thecircumference of the measurement pipe 210, such that multiple sets ofmeasurement data may be collected by the ultrasonic flow meter 132.

In addition, although described herein as an ultrasonic flow meter 132,the flow meter 132 may indeed use any suitable type of sonic energy andany suitable type of sound probes. In fact, the flow meter may employany suitable non-invasive techniques. For instance, thermal-basednon-invasive flow meters may be used, such as where a specific amount ofheat is introduced into the fluid flow and the temperature distributionthrough the fluid may be used to determine characteristics, such asvelocity, of the fluid flow. In addition, optical based non-invasiveflow meters may also be used. In this type of flow meter, beams of lightmay be shown through the fluid flow and the manner in which the lightscatters through the fluid flow may lead to determinations ofcharacteristics of the fluid flow. In addition, other variousnon-invasive techniques (e.g., magnetic resonance, and so forth) mayalso be utilized.

The use of ultrasonic flow meters within the flow regulator 20 may leadto several benefits. For example, other types of flow metering devicesmay require filters since they generally have a lower tolerance forparticulates. This is due, at least in part, to the complexity of themechanical components within these flow metering devices. For instance,since there is only a limited amount of space within the chemicalinjection management system 16, these mechanical flow metering devicesmay often contain small restrictions (e.g., from small moving parts,seals, and so forth) and, as such, may be very sensitive to particulatesin the fluid. However, when using ultrasonic flow meters, there ispotentially less of a need for filtration as ultrasonic flow metersgenerally do not have as many small restrictions since flow measurementis accomplished via acoustic energy instead of mechanical components. Assuch, acoustic flow meters may have a generally high tolerance toparticulates, gels, and semi-solid and solid bodies, which may becarried along within the fluid being measured.

In addition, concerns about chemicals attacking the metering elementsmay be minimized due to the fact that there are fewer mechanicalcomponents in ultrasonic flow meters. More particularly, since theultrasonic flow meter 132 may generally include little more than asimple tube construction, minimal moving parts or seals are required.More specifically, since the transducers 206, 208 may be locatedexternal to the measurement pipe 210, the transducers 206, 208 may beisolated from the actual fluid flow. As such, these main measurementcomponents of the ultrasonic flow meter 132 are not subject to corrosionor chemical attack. In addition, corrosive resistant materials may alsobe used for the tube construction, further limiting potentially adverseaffects of chemicals attacking the ultrasonic flow meter 132.

One particular fluid that may be measured by the ultrasonic flow meter132 is the mono ethylene glycol (MEG), which may be circulated throughthe chemical injection management system 16. In general, the MEG is aglycol which may be re-cycled through the resource extraction system 10in order to suppress the buildup of hydrates. As the MEG is re-cycledthrough the resource extraction system 10, it may begin to accumulateimpurities. However, as described above, ultrasonic flow meters may beless sensitive to impurities than other types of metering devices. Assuch, the measurement of the MEG by ultrasonic flow meters may proveless problematic than with other types of metering devices.

In addition, the use of ultrasonic flow meters may also allow foridentification of blockages (e.g., due to hydrates and so forth) withthe chemical injection management system 16. For instance, usingultrasonic flow meters may allow for the identification of hydrateblockage within the throttling section of the chemical injectionmanagement system 16. Being able to identify hydrate blockages may allowan operator of the chemical injection management system 16 to decidewhen and what type of remedial action may be taken in the event of suchblockages.

Additionally, the use of ultrasonic flow meters may also allowbi-directional flow measurement, as opposed to other types of meteringdevices which may only be configured to measure flow in one direction.For example, ultrasonic flow meters are capable of measuring flow inboth directions due to the fact that acoustic energy is transmitted inboth directions (e.g. between the first transducer 206 and the secondtransducer 208 of FIG. 11). Therefore, the measurement of flow may bedetermined in both directions using similar flow measurement logic. Theability to measure flow in both directions may prove beneficial in thatthe ultrasonic flow meter 132 may be capable of indicating if and whenproduction bore fluids begin traveling back up through the umbilical. Assuch, an operator of the chemical injection management system 16 may beable to take more effective remedial action.

In the context of bi-directional flow, a variety of acts may beperformed based on the direction of fluid flow determined by thecontroller 134. For instance, the direction of fluid flow, or a changein direction, may be logged in memory. In some embodiments, fluid flowin one direction (i.e., forward or reverse) may trigger an audible orvisible warning (e.g., a broken pump warning on a display or speaker),or the valve 128 may be adjusted (e.g., substantially closed).

FIG. 12 illustrates an example of a flow curve through the valve 128.This graph depicts the position of the needle 142 (FIG. 7), as apercentage of a stroke, versus the flow coefficient (Cv) through thevalve 128. The illustrated curve includes a flow control zone 220, astatic zone 222, and a flushing zone 224. In some embodiments, theflushing zone 224 may be used to clear debris from the needle 142.

FIG. 13 illustrates an exemplary valve-adjustment procedure 226. Theillustrated procedure 226 may include measuring a parameter of a fluidflowing through a valve, as illustrated by block 228. This may includethe above-mentioned steps of flowing the fluid through the flow meter132. Next, the procedure 226 may include opening or closing the valve bya first distance, as illustrated by block 230. This may include theabovementioned steps of moving the needle 142 in the valve 128. Theprocedure 226 may also include measuring the parameter of the fluid flowwith the valve opened or closed by the first distance, as illustrated byblock 232, and opening or closing the valve by a second distance, asillustrated by block 234. These acts may again include theabove-mentioned steps of operating the flow meter 132 and the valve 128.Next, the procedure 226 may include measuring the parameter of the fluidflow with the valve opened or closed by the second distance, asillustrated by block 236, a step which may include operating the flowmeter 132. In some embodiments, the measured parameters from the stepsillustrated by blocks 228, 232, and 236, may then be compared to arelationship of the parameter to distance, such as the stroke percentageof the needle 142, stored in memory. Comparing may include comparing themeasured values to the above-mentioned stored correlation between needleposition and flow rate through the valve 128, such as the correlationillustrated by FIG. 12. Finally, in some embodiments, the degree towhich the valve is opened or closed may be adjusted based on thecomparison, as illustrated by block 240.

Returning now to FIG. 11, the use of ultrasonic flow meters may alsoallow for the measurement of other parameters of the fluid flowingthrough the flow meter in addition to fluid velocity and volumetric flowrate of the fluid. For instance, ultrasonic flow meters may also becapable of measuring the density of the fluid. In addition, ultrasonicflow meters may be capable of determining when viscosity changes occurin the fluid. Specifically, the velocity of sound may be correlated todensity and viscosity, as well as contamination of a single fluid.Additionally, the acoustic fluid attenuation is measurable and may becorrelated to the viscosity of the fluid or blockages in the case of asingle fluid. The ability to measure these additional parameters mayprove beneficial in that an operator of the chemical injectionmanagement system 16 may be able to monitor the conditions of the fluidand determine if the fluid is behaving adversely due to particularoperating conditions of the chemical injection management system 16. Inother words, the use of ultrasonic flow meters may allow for enhancedflow conditioning assessment.

In addition, the ultrasonic flow meter 132 may be used either as aprimary flow measurement device or a secondary flow measurement device.In particular, the ultrasonic flow meter 132, in certain embodiments,may be used as a backup flow measurement device. For instance, apositive displacement flow meter, or any other type of flow meter (e.g.,a variable area flow meter, an orifice plate flow meter, and so forth),may be used as the primary flow measurement device while the ultrasonicflow meter 132 is used as a secondary flow measurement device, or viceversa.

The ultrasonic flow meter 132 may be used in conjunction withclosed-loop control by the controller 134 illustrated in FIG. 8. Inaddition, the ultrasonic flow meter 132 may utilize various standardprotocols for transmitting information back to a master control station.For instance, the ultrasonic flow meter 132 may be capable of utilizingthe Can-bus (controller-area network bus) protocol as one approach.However, the ultrasonic flow meter 132 may also be capable of utilizingother digital protocols, such as Profibus (process field bus), Modbus,and so forth.

However, although the use of ultrasonic flow meters may allow fornumerous benefits, it may also present certain challenges as well. Forinstance, as opposed to other types of flow metering devices, ultrasonicflow meters may generally involve numerous calculations. For instance,in order to calculate fluid velocities and volumetric fluid flow asdescribed above with respect to FIG. 11, numerous calculations may bemade taking into account the transit times between the transducers 206,208, particular geometries of the measurement pipe 210 (e.g., the innerdiameter (ID)) and the acoustic path 212 (e.g., the angle θ), and soforth. These various calculations may lead to greater complexity of thecontroller 134 and associated processor 172 and memory 174. In addition,the amount of power used by the controller 134, processor 172, andmemory 174 may increase as well.

Furthermore, only a limited amount of power may be available in thechemical injection management system 16. As such, the use of the limitedpower may be an important design consideration. In order to ensure thatenough power is available for operation of the ultrasonic flow meter132, the flow regulator 20 may include various power-saving andpower-storing mechanisms. For example, an array of capacitors may beused for storing energy for periods of operation when the stored energyis needed (e.g., for pulsing the transducers 206, 208 or for supplyingenergy for various calculations).

In addition, external noise from other components of the chemicalinjection management system 16 may potentially inhibit the accuracy ofthe ultrasonic flow meters. For instance, noise from the othercomponents may interfere with the ability of the transducers 206, 208 toregister the acoustic energy being transmitted between them. However,the external noise may be addressed in a number of various ways, bothmechanical and electrical. For instance, extra shielding and padding maybe placed around the ultrasonic flow meter 132 to reduce the affect ofthe external noise. In addition, the intensity of the acoustic pulsesmay be modified to counteract the adverse affects of the external noise.Additionally, the flow regulator 20 may be designed such that certainelectrical or mechanical components may be turned off, or otherwisecontrolled, during flow measurement periods, such that the externalnoise has a minimal affect on flow measurement accuracy.

It should be noted that the exemplary embodiment of the ultrasonic flowmeter 132 illustrated in FIG. 11 is merely intended to be exemplary andis not the only ultrasonic flow meter design which may be used as pat ofthe flow regulator 20 of the chemical injection management system 16.For instance, FIG. 14 is a cross-sectional view of another exemplaryultrasonic flow meter 132 used with the flow regulator 20. In thisembodiment, the measurement pipe 210 includes a first bend 242 and asecond bend 244. More specifically, the fluid flows into the measurementpipe 210, takes a first turn at the first bend 242, takes a second turnat the second bend 244, and then flows out of the measurement pipe 210.In this embodiment, the transducers 206, 208 are located near the bends242, 244. In particular, the first transducer 206 is located near thefirst bend 242 and the second transducer 208 is located near the secondbend 244. The transducers 206, 208 are pointed toward each other suchthat the acoustic path 212 runs along the measurement pipe 210 from thefirst bend 242 to the second bend 244. As such, in this embodiment, theacoustic energy between the transducers 206, 208 is transmitted eitherdirectly against or directly with the flow of fluid. The fluid velocity,volumetric flow rate, and other parameters of the fluid may still bemeasured as explained above with respect to FIG. 11. However, thespecifics of the calculations used may change slightly due to thedifferences between the geometries of the embodiments in FIGS. 11 and14.

Additionally, although embodiments of the chemical injection managementsystem 16 illustrated in FIGS. 2 through 6 are shown using a particulartechnique for locking the chemical injection management system 16 inplace, other techniques may be used as well. In particular, anotherexemplary technique for locking the chemical injection management system16 in place is illustrated in FIGS. 15 through 18. More specifically,FIG. 15 illustrates an embodiment of a chemical injection managementsystem (C.I.M.S.) insert 246 configured to lock into place within analternative C.I.M.S. receptacle 248, as illustrated in FIG. 16. Inaddition, FIGS. 17 and 18 illustrate the C.I.M.S. insert 246 of FIG. 15locked into place within the C.I.M.S. receptacle 248 of FIG. 16.

In particular, as illustrated, the C.I.M.S. insert 246 may include afluid-inlet connector 66 and a fluid-outlet connector 68, which mayconnect with the fluid inlet 86 and fluid outlet 88, respectively, ofthe C.I.M.S. receptacle 248. The fluid-inlet connector 66 and afluid-outlet connector 68 may lead to and through the valve 130 and flowmeter 132, which are described in greater detail above. As discussedabove, the flow meter 132 may in certain embodiments be an ultrasonicflow meter. The C.I.M.S. insert 246 also includes locking members 250,which may be configured to mate with a flange 252 of the C.I.M.S.receptacle 248. In particular, the flange 252 may have a recess orcircular grooves 254, which have a conforming shape with the lockingmembers 250 of the C.I.M.S. insert 246. A sliding sleeve 256 may beforced behind the locking members 250 to hold them into the conforminggrooves 254 after the C.I.M.S. insert 246 is in place.

The C.I.M.S. insert 246 also has a lower support plate 258 which may beconnected to the tree 14 or a manifold. In addition, a seal 260 may beused to seal out seawater between the lower support plate 258 of theC.I.M.S. insert 246 and the flange 252 of the C.I.M.S. receptacle 248. Ahousing 262, in conjunction with the lower support plate 258, may definean opening through which the locking members 250 may move radially for alock into the grooves 254 of the flange 252 of the C.I.M.S. receptacle248.

The sliding sleeve 256 has an inner seal 264, an outer seal 266, and acavity 268 adjacent the outer seal 266. The inner seal 264 may, forinstance, seal against internal components of the C.I.M.S. insert 246which are not specifically shown. The cavity 268 may be connected to ahydraulic pressure source 270. By providing pressurized hydraulic fluidinto the cavity 268, the increase in pressure may raise the slidingsleeve 256 as a backup way to retract the locking members 250 forrelease of the C.I.M.S. insert 246. Otherwise, the locking members 250may move radially outward by applying axial force on one of the rods 272in an axial direction 273 toward the lower end of the C.I.M.S. insert246. The rods 272 extend through a sealed housing 274, which may befilled with a lubricant and may be sealed to exclude seawater as therods 272 are moved in opposite axial directions 275 by the ROV (notshown). A plate 276 may move in tandem with the rods 272. In addition,another rod 278 may be connected to the plate 276 and the sliding sleeve256. As a result, when the ROV moves one of the rods 272 down axially(e.g., as indicated by arrow 273), the sliding sleeve 256 moves downaxially as well and the locking members 250 move radially into thecircular grooves 254 of the flange 252 of the C.I.M.S. receptacle 248.To release the C.I.M.S. insert 246, the rods 272 may be raised axiallyand the C.I.M.S. insert 246 will move out of the locked position, sincethe locking members 250 become unsupported after retraction of thesliding sleeve 256. In addition, as a backup method for moving thesliding sleeve 256 up axially, hydraulic pressure may be applied to thecavity 268.

Using the alternative embodiments of the C.I.M.S. insert 246 and theC.I.M.S. receptacle 248 illustrated in FIGS. 15 through 18 may lead toseveral benefits. The seals (e.g., the inner seal 264 and the outer seal266) may keep circulating seawater away from the locking members 250,thus minimizing the adverse affects of debris and corrosion on thelocking members 250. In addition, the moving parts that operate thesliding sleeve 256 are disposed within the housing 274, which excludesseawater and, as explained above, may be filled with a lubricatingfluid. By placing these components in a lubricating fluid, the designlife may be improved while corrosion, algae growth, and debris may beprevented. In addition, only a portion of the rods 272 extend from thehousing 274 and are directly exposed to seawater. Furthermore, seals 280may block seawater from entering the housing 274 near the rods 272.

It should also be noted that while only one C.I.M.S. insert 246 is shownlocked into place within the C.I.M.S. receptacle 248 in FIGS. 15 through18, multiple combinations of chemical injection management systems 16and C.I.M.S. inserts 246 may actually be used within a single C.I.M.S.receptacle 248. As such, multiple chemical injection management systems16 and C.I.M.S. inserts 246 may be configured to operate in tandemwithin the C.I.M.S. receptacle 248. For instance, FIG. 19 illustratesmultiple chemical injection management systems 16 within a singleC.I.M.S. insert 246. As illustrated, C.I.M.S. insert connection valves282 may link multiple chemical injection management systems 16 within asingle C.I.M.S. insert 246. In addition, other components of thechemical injection management systems 16 and the C.I.M.S. inserts 246may similarly be configured to connect with each other.

By combining multiple chemical injection management systems 16 andC.I.M.S. inserts 246, space within the tree 14 or manifold may be saved.Furthermore, common components of the resource extraction system 10(e.g., electrical umbilicals, lockdown components, volume compensationequipment, and so forth) may be utilized when multiple chemicalinjection management systems 16 are located within a single C.I.M.S.insert 246. In addition, having only one retrievable package may aid inthe replacement of the C.I.M.S. inserts 246.

While the invention may be susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and have been described in detail herein.However, it should be understood that the invention is not intended tobe limited to the particular forms disclosed. Rather, the invention isto cover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the followingappended claims.

The invention claimed is:
 1. A system, comprising: a chemical injectionunit, comprising: a housing; a tree interface coupled to the housing,wherein the tree interface comprises a chemical inlet, a chemicaloutlet, and a mechanical connector configured to couple the chemicalinjection unit to a tree of a mineral extraction system; a fluid pathextending through the housing from the chemical inlet to the chemicaloutlet; a valve disposed along the fluid path within the housing; and anon-invasive meter disposed along the fluid path within the housing,wherein the non-invasive meter comprises first and second transducersthat are external to the fluid path, the first and second transducersare offset from one another by an offset distance, the first transduceris configured to transmit a first energy through the fluid path to thesecond transducer, and the second transducer is configured to transmit asecond energy through the fluid path to the first transducer.
 2. Thesystem of claim 1, wherein the non-invasive meter comprises anultrasonic flow meter, the first energy comprises a first ultrasonicenergy, and the second energy comprises a second ultrasonic energy. 3.The system of claim 1, wherein the non-invasive meter isbi-directionally configured to measure one or more parameters in a firstflow direction through the fluid path and a second flow directionthrough the fluid path, and the first and second flow directions areopposite to one another.
 4. The system of claim 1, wherein the first andsecond transducers are disposed coaxial with an axis of the fluid path.5. The system of claim 4, wherein the first transducer is disposedadjacent a first bend in the fluid path and the second transducer isdisposed adjacent a second bend in the fluid path.
 6. The system ofclaim 1, wherein the first and second transducers are longitudinallyoffset from one another.
 7. The system of claim 1, wherein the first andsecond transducers are disposed circumferentially about the fluid path.8. The system of claim 1, wherein the non-invasive meter comprises noiseshielding disposed about the first and second transducers.
 9. The systemof claim 1, wherein the non-invasive meter comprises a power savingfeature, a power storing feature, or a combination thereof.
 10. Thesystem of claim 1, wherein the non-invasive meter comprises a noisereduction feature configured to turn off one or more noise generatingcomponents during a measurement by the first and second transducers. 11.The system of claim 1, comprising a controller coupled to thenon-invasive meter, wherein the non-invasive meter is configured tomeasure one or more parameters based on a comparison of a firsttransmission of the first energy from the first transducer to the secondtransducer and a second transmission of the second energy from thesecond transducer to the first transducer.
 12. The system of claim 11,wherein the comparison comprises a difference in transmission times ofthe first transmission versus the second transmission.
 13. The system ofclaim 1, wherein the first and second energies comprise acoustic energy,thermal energy, optical energy, or magnetic energy.
 14. The system ofclaim 1, wherein the non-invasive meter is configured to measure a flowrate, a fluid velocity, or a combination thereof, of a fluid flowthrough the fluid path.
 15. The system of claim 1, wherein thenon-invasive meter is configured to measure a density, a viscosity, or acombination thereof, of a fluid flow through the fluid path.
 16. Thesystem of claim 1, wherein the non-invasive meter is configured tomeasure one or more parameters to identify a contaminant, a blockage, ora combination thereof, in a fluid flow.
 17. The system of claim 1,comprising the tree of the mineral extraction system coupled to thechemical injection unit.
 18. A system, comprising: a chemical injectionunit, comprising: a housing; a tree interface coupled to the housing,wherein the tree interface comprises a chemical inlet, a chemicaloutlet, and a mechanical connector configured to couple the chemicalinjection unit to a tree of a mineral extraction system; a fluid pathextending through the housing from the chemical inlet to the chemicaloutlet; a valve disposed along the fluid path within the housing; and anon-invasive meter disposed along the fluid path within the housing,wherein the non-invasive meter comprises noise shielding.
 19. The systemof claim 18, wherein the non-invasive meter is bi-directionallyconfigured to measure one or more parameters in a first flow directionthrough the fluid path and a second flow direction through the fluidpath, and the first and second flow directions are opposite to oneanother.
 20. The system of claim 19, wherein the non-invasive metercomprises an ultrasonic flow meter, and the one or more parameterscomprise a flow measurement.
 21. A system, comprising: a chemicalinjection unit, comprising: a housing; a tree interface coupled to thehousing, wherein the tree interface comprises a chemical inlet, achemical outlet, and a mechanical connector configured to couple thechemical injection unit to a tree of a mineral extraction system; afluid path extending through the housing from the chemical inlet to thechemical outlet; a valve disposed along the fluid path within thehousing; and a non-invasive meter disposed within the housing, whereinthe non-invasive meter is configured to transmit energy at leastpartially coaxial with an axis of the fluid path.
 22. The system ofclaim 21, wherein the non-invasive meter comprises an ultrasonic flowmeter.
 23. The system of claim 21, wherein the non-invasive meter isconfigured to measure one or more parameters to identify a contaminant,a blockage, or a combination thereof, in a fluid flow.
 24. A system,comprising: a chemical injection unit, comprising: a housing; a treeinterface coupled to the housing, wherein the tree interface comprises achemical inlet, a chemical outlet, and a mechanical connector configuredto couple the chemical injection unit to a tree of a mineral extractionsystem; a fluid path extending through the housing from the chemicalinlet to the chemical outlet; a valve disposed along the fluid pathwithin the housing; and a non-invasive meter disposed along the fluidpath within the housing, wherein the non-invasive meter comprises anoise reduction feature configured to turn off one or more noisegenerating components during a measurement by the non-invasive meter.